Personal hygiene articles which are designed to absorb fluids, particularly body fluids such as blood, urine, pus and the like, include items such as tampons, sanitary napkins, diapers, bibs, incontinence pads, surgical sponges, compresses, bandages, and wipes. An important component of these articles is the absorbent material, generally known as fluff, which may be made from cellulosic fibers or synthetic fibers or a combination of cellulosic and synthetic fibers. As used in these articles, fluff is intended to provide one of two functions, to wick fluid away from the surface of the article and transport the fluid to an internal location within the product away from the surface of the article or to absorb and retain an amount of fluid so that the surface of the article remains dry. Fibers may be formed with different properties depending on which of the two functions is more desirable. Cellulosic fibers may be used as fluff in these articles because they are relatively inexpensive and are typically inert to human body chemistry, thus they do not create any unwanted side effects associated with their use.
It has long been a goal of the fiber processing industry, and the industries which they supply, to develop improved fiber structures that can transport and retain an increased amount of fluid at a higher rate of absorbency. Additionally, the ability to handle several repeated instances of fluid wetting and transport is seen as greatly desirable for many personal hygiene products, as exemplified by a diaper intended for overnight use.
The most desirable fibers for use as fluff in disposable personal hygiene articles are cellulosic fibers of wood prepared according to conventional techniques. Such fibers are readily available and are low cost. Unfortunately, commercially available cellulosic fibers have a tendency to bond together as they dry after an initial wetting. Bonding of the fibers causes the fluff to clump into a mass that is no longer able to absorb and transport liquid in the amount or at the rate observed during the first wetting. Accordingly, the performance of known cellulosic fibers is less than optimal for the personal hygiene articles made containing such fibers.
In response to this problem, various modifications of the fibers have been devised which are intended to enhance the multiple wetting transport properties of the fluff in personal hygiene articles. Unfortunately, these modifications tend to have significant deficiencies, not the least of which is the increased cost of manufacturing. Additionally, fibers treated with organic compounds to improve their transport properties may give off formaldehyde or other residues of the organic cross-linking agents or catalysts which cannot be completely removed from the fibers. Thus, personal hygiene articles containing organically treated fibers may release unpleasant odors or they may increase the amount of skin irritation associated with the articles. Furthermore, the extreme process conditions and length of time required for treating the fibers are significant deficiencies of the currently used methods for increasing the fluid transport properties of cellulosic fibers.
Thus, there is a need for personal hygiene articles containing inexpensively processed, absorbent fibers. The fibers should have fluid transport properties which remain effective to transport and retain fluids even upon repeated wetting and/or compression of the fibers. Furthermore, the fibers should be substantially free of skin irritants and/or odor releasing substances.
Accordingly, it is an object of the present invention to provide an improved personal hygiene article for absorbing fluids.
It is another object of the invention to provide an improved personal hygiene article containing a cellulosic fiber fluff having improved fluid transport properties.
It is a further object of the invention to provide an improved personal hygiene article containing a wood fiber fluff for transporting and retaining fluids in a location away from the surface of the article.
It is yet another object of the invention to provide an improved personal hygiene article wherein the fiber fluff retains its fluid transport and fluid retention properties through several wetting episodes even after compression of the fibers.